stable inclusion
from stable-5.10.37
commit 87856f9af04eaacf9848710625a4ffee1d020fa9
bugzilla: 51868
CVE: NA

--------------------------------

[ Upstream commit 4aeec398 ]

vfio_add_group_dev() must be called only after all of the private data in
vdev is fully setup and ready, otherwise there could be races with user
space instantiating a device file descriptor and starting to call ops.

For instance vfio_pci_reflck_attach() sets vdev->reflck and
vfio_pci_open(), called by fops open, unconditionally derefs it, which
will crash if things get out of order.

Fixes: cc20d799 ("vfio/pci: Introduce VF token")
Fixes: e309df5b ("vfio/pci: Parallelize device open and release")
Fixes: 6eb70187 ("vfio-pci: Move idle devices to D3hot power state")
Fixes: ecaa1f6a ("vfio-pci: Add VGA arbiter client")
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMax Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: NKevin Tian <kevin.tian@intel.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Message-Id: <8-v3-225de1400dfc+4e074-vfio1_jgg@nvidia.com>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>